Adjustable deflection unit for television picture tubes

ABSTRACT

A deflection coil mounting device permits axial adjustment of the coil which is supported within a basket element around the neck of the tube. The device includes a rotatable ring mounted on the basket and having an external screw thread which is rotated through guide elements on an inner housing secured to the coil. Rotation of the ring causes axial movement of the coil and housing. Elastic safety hooks hold the ring in position and projections at the ends of the thread limit the movement.

i United States Patent Bissinger Sept. 16, 1975 [54] ADJUSTABLE DEFLECTION UNIT FOR 2,817,034 12/1957 Covill 335/210 TELEVISION PICTURE TUBES 3,582,848 6/1971 Ryder et al. l78/7.8l 3,772,978 11/1973 Mito 350/187 [75] Inventor: Norbert Bissinger, Uhingen, 7

Germany FOREIGN PATENTS OR APPLICATIONS Assigneec International standard Electric 676,629 7/1952 UmtedKmgdom 313/75 C t' N Y k, N Y.

orpora ew or Primary Examiner-Alfred E. Smith Filed! P 1973 Assistant Examiner-Emest R'Karlsen Attorne A em or Firm-John T. Ol'lalloran' 21 A LN .1395897 8 1 1 pp 0 Menotti J. Lombardi, Jr.; Peter C. Van Der Sluys [30] Foreign Application Priority Data [57] ABSTRACT Oct. 2, 1972 Germany 224831 1 A deflection coil mounting device permits axial adjust 3 5 21 ment of the coil which is Supported within a basket 5' "01F 3 6 ement around the neck of the tube. The device 1n- [58] Fieid 313/75 76 421 426 cludes a rotatable ring mounted on the basket and 313/427 335/212 5 having an external screw thread which is rotated through guide elements on an inner housing secured I to the coil. Rotation of the ring causes axial movement [56] References Cited of the coil and housing. Elastic safety hooks hold the ring in position and projections at the ends of the UNITED STATES PATENTS thread limit the movement.

2,568,631 9/1951 Hoellerich 313/75 0 2,694,782 11/1954 lngle 313/75 6 Clams, 5 Drawmg Flgules PAIENIEBSEP 16 ms SHEET 1 or q Fig. 7a

PATENTED SEP 1 61975 SHEET 2 BF Fig. 2

PATENTEB SEP I 6 i975 sum 3 qg g PATENTED SEP I 6 I975 swung ADJUSTABLE DEFLECTION UNIT FOR TELEVISION PICTURETUBES BACKGROUND OF THE INVENTION 1. Field of the Invention I v l v The present invention relates to adeflecti on unit for color television picture tubes and'particul'arly for tubes with a toroidaldeflection coil which is axially'hnd/or radially adjustable and rotatable.

2. Description of the Prior Art The fixing of the operating position of the deflection unit on the neck of a color television tube requires an adjusting device in addition to the usual structural measures such as centering and the provision of stops. This is necessary because of manufacturing and other variations which are always present. In one known adjusting device, the basket of a deflection unit has an adjusting ring with helical oblong holes distributed along the circumference. Sliding in these oblong holes are bolts which are radially attached to a ring which, in turn, is securely mounted on the coil yoke. The free ends of the bolts, which slide in the oblong holes, have a thread onto which locking nuts are screwed from the outside of the adjusting ring. This type of adjusting device requires a major number of fastening bolts and a corresponding number of oblong holes in the adjusting ring if sufficient ruggedness is to be insured.

SUMMARY OF THE INVENTION It is the object of the present invention to provide a deflection unit having an adjusting device of improved ruggedness and which offers advantages in manufacture and operation.

The device includes a ring rotatable about the longitudinal axis of the deflection unit and mounted on the coil basket. The outside of the ring is provided with a screw thread whose pitch corresponds to the predetermined axial travel of the deflection coil. Several guide elements are disposed symmetrically along the circumference of the internal housing in engagement with the screw thread and connected permanently with the deflection coil. In order to operate the adjusting ring, the latter has outwardly directed projections which are located at one end of each thread and serve as stops. In addition, the housing has a number of nose-like projections which are distributed along the inner circumference to permit easy sliding along the coil basket.

Other advantages and details of the invention will become more apparent from the following description of the invention taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1a is a side view of the coil basket as mounted on a tube;

FIG. 1b shows a detailed portion of FIG. 1a;

FIG. 2 is a partial top view of the coil basket;

FIG. 3 shows the internal housing, connected permanently with the deflection coil; and

FIG. 4 shows a partial sectional view of the assembly.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The deflection unit essentially comprises the coil basket 10, the internal housing 30, and the deflection coil 13, which is permanently connected with the internal housing. The coil basket is supported on the television picture tube envelope l4 by legs-11 which rest on theneckofthetube. w

As shown in FIGS. 1a and 1b, the coil basket 10 carries aring 2 on the side opposite the legs 11. This ring 20 is rotatably mounted on the coil basket 10. To prevent the ring 20, which isslipped on the coil basket 10, from slipping off again, the coil basket has hooklike' guards 12, referred to as safety hooks. These safety books 12 are elastic and shaped so as to yield toward the inside when the ring 20 is slipped on, then resiliently projecting beyond the rim of the ring 20. As shown in FIG. 2, the ring 20 may also have grooves 23 through which the safety hooks 12 slide as the ring is slipped on. It must be insured that the grooves 23 lie in a circumferential area of the ring 20 which is not reached by the safety hooks 12 when the ring is turned in operation. Along its circumference, the ring 20 has a thread-like projection 21, as seen in FIGS. 1a and 1b. This thread is engaged by a guide element 31 which is a portion of the internal housing 30. The guide element 31 consists of two like parts 311 and 312 for improved sturdiness.

As further shown in FIG. 3, when the ring 20 is turned where it has projecting handles 22, the guide elements 31 slide on the thread plane, and the internal housing 30 with the deflection coil is axially shifted. Conventional guides assure that no twisting of the internal housing 30 with respect to the deflection coil takes place. The housing 30 has projections 32 on the inner circumference which facilitate sliding along the coil basket.

In practice, this adjusting device has turned out to be highly reliable in service as a result of its simple and rugged construction. The fineness of adjustment depends on the choice of the thread pitch, or step-down ratio. The projecting handles 22 are advantageously located at the end of the thread 21 where they simultaneously serve as stops.

What is claimed is:

l. A deflection unit for a television picture tube comprising an outer support structure secured around the neck of the tube, an inner axially adjustable housing mounted on said support structure, a deflection coil secured to said inner housing and extending around said tube neck, a ring rotatably mounted onsaid outer support about the longitudinal axis of the deflection unit and along the neck of said tube, the outside of said ring having a screw thread whose pitch corresponds to the predetermined maximum axial travel of the deflection coil and inner housing, and a plurality of longitudinal guide elements secured about the circumference of the inner housing and extending outwardly along and about said ring in sliding engagement with the screw thread to cause axial movement of said inner housing and deflection coil with rotation of said ring.

2. The device of claim 1 wherein said inner housing has projections on the base of the inner circumference slidably engaging the outer support structure around the neck of said tube.

3. The device of claim 2 including two resilient safety hooks on said inner housing extending from within said ring along the neck of said tube beyond the inside diameter of the ring providing an axial stop for said ring.

4. The device of claim 3 wherein the inside of the ring has axial grooves for insertion of said safety hooks, the grooves being in a circumferential region outside the position of the safety hooks when the ring is turned.

side of said ring having a screw thread whose pitch corresponds to the predetermined maximum axial travel of said inner housing; and a plurality of longitudinal guide elements secured about the circumference of the inner housing and extending outwardly along and about said ring sliding engagement with the screw thread to cause axial movement of said inner housing with rotation of said ring. 

1. A deflection unit for a television picture tube comprising an outer support structure secured around the neck of the tube, an inner axially adjustable housing mounted on said support structure, a deflection coil secured to said inner housing and extending around said tube neck, a ring rotatably mounted on said outer support about the longitudinal axis of the deflection unit and along the neck of said tube, the outside of said ring having a screw thread whose pitch corresponds to the predetermined maximum axial travel of the deflection coil and inner housing, and a plurality of longitudinal guide elements secured about the circumference of the inner housing and extending outwardly along and about said ring in sliding engagement with the screw thread to cause axial movement of said inner housing and deflection coil with rotation of said ring.
 2. The device of claim 1 wherein said inner housing has projections on the base of the inner circumference slidably engaging the outer support structure around the neck of said tube.
 3. The device of claim 2 including two resilient safety hooks on said inner housing extending from within said ring along the neck of said tube beyond the inside diameter of the ring providing an axial stop for said ring.
 4. The device of claim 3 wherein the inside of the ring has axial grooves for insertion of said safety hooks, the grooves being in a circumferential region outside the position of the safety hooks when the ring is turned.
 5. The device of claim 4 wherein the screw thread has a projection at the end thereof providing a rotational stop element.
 6. A coil adjustment unit for a cathode ray tube comprising an outer support structure secUred around the neck of the tube; an inner axially adjustable housing mounted on said support structure and adapted to hold a coil extending around said tube neck; a ring rotatably mounted on said outer support about the longitudinal axis of the unit and along the neck of said tube, the outside of said ring having a screw thread whose pitch corresponds to the predetermined maximum axial travel of said inner housing; and a plurality of longitudinal guide elements secured about the circumference of the inner housing and extending outwardly along and about said ring in sliding engagement with the screw thread to cause axial movement of said inner housing with rotation of said ring. 